Method of manufacture for an ultraviolet laser diode

ABSTRACT

A method for fabricating a laser diode device includes providing a gallium and nitrogen containing substrate member comprising a surface region, a release material overlying the surface region, an n-type gallium and nitrogen containing material; an active region overlying the n-type gallium and nitrogen containing material, a p-type gallium and nitrogen containing material; and a first transparent conductive oxide material overlying the p-type gallium and nitrogen containing material, and an interface region overlying the first transparent conductive oxide material. The method includes bonding the interface region to a handle substrate and subjecting the release material to an energy source to initiate release of the gallium and nitrogen containing substrate member.

CROSS-REFERENCES TO RELATED APPLICATIONS

This application is a continuation of U.S. application Ser. No.14/968,710, filed Dec. 14, 2015, which is a continuation of U.S.application Ser. No. 14/534,636, filed Nov. 6, 2014, the disclosures ofwhich are incorporated by reference herein in their entirety.

BACKGROUND

In 1960, the laser was first demonstrated by Theodore H. Maiman atHughes Research Laboratories in Malibu. This laser utilized asolid-state flashlamp-pumped synthetic ruby crystal to produce red laserlight at 694 nm. By 1964, blue and green laser output was demonstratedby William Bridges at Hughes Aircraft utilizing a gas laser designcalled an Argon ion laser. The Ar-ion laser utilized a noble gas as theactive medium and produce laser light output in the UV, blue, and greenwavelengths including 351 nm, 454.6 nm, 457.9 nm, 465.8 nm, 476.5 nm,488.0 nm, 496.5 nm, 501.7 nm, 514.5 nm, and 528.7 nm. The Ar-ion laserhad the benefit of producing highly directional and focusable light witha narrow spectral output, but the wall plug efficiency was <0.1%, andthe size, weight, and cost of the lasers were undesirable as well.

As laser technology evolved, more efficient lamp pumped solid statelaser designs were developed for the red and infrared wavelengths, butthese technologies remained a challenge for blue and green and bluelasers. As a result, lamp pumped solid state lasers were developed inthe infrared, and the output wavelength was converted to the visibleusing specialty crystals with nonlinear optical properties. A green lamppumped solid state laser had 3 stages: electricity powers lamp, lampexcites gain crystal which lases at 1064 nm, 1064 nm goes into frequencyconversion crystal which converts to visible 532 nm. The resulting greenand blue lasers were called “lamped pumped solid state lasers withsecond harmonic generation” (LPSS with SHG) had wall plug efficiency of˜1%, and were more efficient than Ar-ion gas lasers, but were still tooinefficient, large, expensive, fragile for broad deployment outside ofspecialty scientific and medical applications. Additionally, the gaincrystal used in the solid state lasers typically had energy storageproperties which made the lasers difficult to modulate at high speedswhich limited its broader deployment.

To improve the efficiency of these visible lasers, high power diode (orsemiconductor) lasers were utilized to replace the inefficient andfragile lamps. These “diode pumped solid state lasers with SHG” (DPSSwith SHG) had 3 stages: electricity powers 808 nm diode laser, 808 nmexcites gain crystal which lases at 1064 nm, 1064 nm goes into frequencyconversion crystal which converts to visible 532 nm. The DPSS lasertechnology extended the life and improved the wall plug efficiency ofthe LPSS lasers to 5%-10%, and further commercialization ensue into morehigh-end specialty industrial, medical, and scientific applications.However, the change to diode pumping increased the system cost andrequired precise temperature controls, leaving the laser withsubstantial size, power consumption while not addressing the energystorage properties which made the lasers difficult to modulate at highspeeds.

As high power laser diodes evolved and new specialty SHG crystals weredeveloped, it became possible to directly convert the output of theinfrared diode laser to produce blue and green laser light output. These“directly doubled diode lasers” or SHG diode lasers had 2 stages:electricity powers 1064 nm semiconductor laser operating withlongitudinal mode (single frequency) and single spatial mode, 1064 nmgoes into frequency conversion crystal, which converts to visible 532 nmgreen light. These lasers designs are meant to improve the efficiency,cost and size compared to DPSS-SHG lasers, but the specialty single modediodes, high precision laser beam alignment, and crystals required makethis challenging today. Additionally, while the diode-SHG lasers havethe benefit of being directly modulate-able, they suffer from severesensitivity to temperature, which limits their application.

Ultraviolet (UV) semiconductor laser diodes (LDs) are becoming a keytechnology for a number of applications such as bio-/chemical photonics,material processing, and high-density data storage. UV spectral band canbe divided into UV-AI 340-400 nm, UV-AII 320-340 nm, UV-B 280-320 nm,and UV-C 280 nm in terms of effects on bio-organic and chemicalsubstances.

SUMMARY

The present disclosure relates generally to optical techniques. Morespecifically, the present disclosure provides methods and deviceconfigurations for the formation of direct emitting laser diodesoperating in the ultraviolet regime using nonpolar, semi-polar, or polarc-plane oriented gallium and nitrogen containing substrates for opticalapplications ranging in the ultraviolet (UV) spectral region, amongothers, including combinations thereof, and the like. Historically, therealization of high quality, high performance laser diodes operating inthe UV range has been challenging for several reasons. First, since therelatively small bandgap of GaN compared to most UV wavelengths ofinterest will result in excessive optical absorption, the use of nativeGaN substrates in the laser structure as a component of the claddingregion will lead to high internal loss within the laser diode. Thisforces either impractical growth of highly-strained, high-aluminumcontent ternary AlGaN cladding layers that will crack and becomedefective, the use of strain controlled high-aluminum content quaternaryInAlGaN cladding layers that are impractical to grow on the thicknessscale required for cladding regions, or the growth of the UV laser diodeepi structures on foreign substrates such as AlN, silicon carbide, orsapphire. The latter approach is commonly deployed, but such devicessuffer from excessive extended defects can create issues in the lightemitting quantum well layers and reduce efficiency. Second, since suchUV lasers require high aluminum content AlxGa(1−x)N (x>0.05, x>0.10,x>0.20, x, >0.30, x>0.40, x>0.50) quantum wells, barriers, and claddingregions the accumulated strain from the layers results in cracking andother material defects that limit the performance and lifetime of thelaser diode. The growth of AlGaN layers with high AlN mole fractions,which are typically used as cladding layers to achieve optical andelectrical confinement, is very difficult because of issues with poorcrystalline quality. As a result of tensile strain, epitaxial AlGaNlayers grown on substrates such as sapphire, AlN, SiC, and GaN sufferfrom dislocations and crack formation, in particular at higher AlN molefractions or for thicker layers. AlGaN materials with high AlN molefractions and having high crystalline quality (low dislocation densityand crack-free) are necessary for the fabrication of high-performancedevices.

This invention overcomes the challenges associated with conventional andknown techniques for fabrication of UV laser diodes. First, by growingan epi stack containing only thin (<500 nm) n and p-type AlGaN claddingregions and/or waveguide regions and an active region comprised of 1 ormore AlGaN quantum wells and barriers on a native GaN substrate, thetotal epi stack of highly tensile strained material can be thin tomitigate stress induced defects. Moreover, since the growth is initiatedon a native GaN substrate the epitaxial interface will be pseudomorphicand be free from the defects present that form when growing on a foreignsubstrate.

The ability to keep the epitaxially grown portion of the cavity thinalso enables the use of quaternary films (i.e. those composed of somecomposition of InGaAlN) for the production of nominally strain freecladding. Compositional control of quaternaries both run-to-run andwithin a single growth over the entire thickness of films is quitedifficult when the film thickness exceeds several hundred nanometers. Bykeeping the quaternary cladding region thin two advantages are gained.Firstly, the thickness over which a uniform composition of quaternarythat must be grown is reduced and, secondly, by reducing the thicknessof the quaternary cladding one is able to grow cladding with higherstrain due to unintentional variation in composition, either fromrun-to-run variation or within the thickness of the film, with exceedingthe critical thickness for forming extended defects that relieve strain.This second benefit reduces increases the tolerances for compositionthat one may accept in the growth process, leading to higher yield andlower defectivity.

By lifting this thin AlGaN containing epitaxy layer structure off thebulk GaN substrate to transfer it to a carrier wafer and sandwiching theAlGaN quantum wells and barriers between high absorption edgetransparent conductive oxide layers (TCO) to form the remainder or thecladding regions, and bonding the stack to a high bandgap substrate suchas AlN the optical absorption of the cladding and substrate region canbe low. The result will be a high quality AlGaN based active region withlow loss cladding and substrate materials. It is critical that the TCObe carefully selected such that it has appropriate conductivity and hasa high energy absorption edge such that optical losses will be minimizedin the UV spectral region. Gallium oxide has been recognized as apromising candidate for deep-ultraviolet transparent conductive oxideswith a direct absorption edge of above 4.7 eV or <263 nm (APPLIEDPHYSICS LETTERS VOLUME 81, NUMBER 2 8 Jul. 2002). This inventioncombines a novel method for transferring high quality gallium andnitrogen UV laser epitaxial structures from bulk gallium and nitrogencontaining substrates to carrier wafers and positioning the saidepitaxial structure between TCO cladding regions that are transparent inthe deep UV spectral range to form a high performance direct emitting UVlaser diode.

In an example, the present invention provides a method for fabricating alaser diode device. The method includes providing a gallium and nitrogencontaining substrate member comprising a surface region, a releasematerial overlying the surface region, an n-type aluminum, gallium, andnitrogen containing material; an active region overlying the n-typealuminum, gallium, and nitrogen containing material, a p-type aluminum,gallium, and nitrogen containing material; and a first transparentconductive oxide material overlying the p-type aluminum, gallium, andnitrogen containing material, and an interface region overlying thefirst transparent conductive oxide material. The method includes bondingthe interface region to a handle substrate and subjecting the releasematerial to an energy source to initiate release of the gallium andnitrogen containing substrate member.

In an example, the interface region is comprised of metal, asemiconductor and/or another transparent conductive oxide. In anexample, the interface region comprises a contact material.

In an example, the energy source is selected from a light source, achemical source, a thermal source, or a mechanical source, and theircombinations. In an example, the release material is selected from asemiconductor, a metal, or a dielectric. In an example, the releasematerial is selected from GaN, InGaN, AlInGaN, or AlGaN such that theInGaN is released using PEC etching. In an example, the active regioncomprises a plurality of quantum well regions.

In an example, the method comprises forming a ridge structure configuredwith the n-type aluminum, gallium, and nitrogen containing material toform an n-type ridge structure, and forming a dielectric materialoverlying the n-type aluminum, gallium, and nitrogen containingmaterial, and forming a second transparent conductive oxide materialoverlying an exposed portion of the n-type aluminum, gallium, andnitrogen containing material or overlying an exposed portion of a n-typegallium and nitrogen containing material overlying the n-type aluminum,gallium, and nitrogen containing material such that active region isconfigured between the first transparent conductive oxide material andthe second conductive oxide material to cause an optical guiding effectwithin the active region. In an example, the method includes forming ann-type contact material overlying an exposed portion of the n-typealuminum, gallium, and nitrogen containing material or forming an n-typecontact material overlying a conductive oxide material overlying anexposed portion of the n-type aluminum, gallium, and nitrogen containingmaterial. In an example, the method includes forming an n-type contactregion overlying an exposed portion of the n-type aluminum, gallium, andnitrogen containing material or an exposed portion of an n-type galliumand nitrogen containing material overlying the n-type aluminum, gallium,and nitrogen containing material; forming a patterned transparent oxideregion overlying a portion of the n-type contact region; and forming athickness of metal material overlying the patterned transparent oxideregion; wherein the p-type aluminum, gallium, and nitrogen containingmaterial is configured as a ridge waveguide structure to form a p-typeridge structure.

In another example the method comprises depositing a transparentconductive oxide over an exposed planar n-type or p-type aluminum,gallium, and nitrogen containing material or over an exposed planarn-type or p-type gallium and nitrogen containing material and thenforming a ridge structure within the transparent conductive oxide toprovide lateral waveguiding. The ridge structure can be formed throughdry etching, wet etching, or a lift-off technique. In an example, thetransparent conductive oxide is comprised of gallium oxide, indium tinoxide, indium gallium zinc oxide, or zinc oxide. In a preferredembodiment transparent conductive oxides for laser cladding is a galliumoxide (for example beta Ga2O3 among other stoichiometries of galliumoxide). Gallium oxide can be deposited either via sputtering,evaporation, or growth from aqueous solution or via a chemical orphysical vapor deposition. Gallium oxide may be grown epitaxially on thegallium and nitrogen containing layers via metal organic chemical vapordeposition or molecular beam epitaxy among other growth techniques.Gallium oxide conductivity can be controlled either by introduction ofextrinsic defects such as alloying with dopant species such as, but notlimited to, nitrogen, zinc and silicon among others. Conductivity andband-gap can also be controlled by alloying gallium oxide with indiumoxide, indium tin oxide alloys, zinc oxide, aluminum oxide and tin oxideamong others. In some embodiments the TCO layers may consist of severalor more layers of different composition. For example, a thin (less than50 nm thick) but highly conductive gallium oxide contact layer may beused to provide good electrical contact while a thicker (100-200 nm)indium tin oxide layer is used to provide electrical conductivity andlower loss.

In an example, the transparent conductive oxide is overlaid on anexposed planar n-type or p-type aluminum, gallium, and nitrogencontaining material or over an exposed planar n-type or p-type galliumand nitrogen containing material using direct wafer bonding of thesurface of the aluminum, gallium, and nitrogen containing material tothe surface of a carrier wafer comprised primarily of TCO or coated inTCO layers. In both cases the TCO surface of the carrier wafer and theexposed aluminum, gallium and nitrogen containing material are cleanedto reduce the amount of hydrocarbons, metal ions and other contaminantson the bonding surfaces. The bonding surfaces are then brought intocontact and bonded at elevated temperature under applied pressure. Insome cases the surfaces are treated chemically with one or more ofacids, bases or plasma treatments to produce a surface that yields aweak bond when brought into contact with the TCO surface. For examplethe exposed surface of the gallium containing material may be treated toform a thin layer of gallium oxide, which being chemically similar tothe TCO bonding surface will bond more readily. Furthermore the TCO andnow gallium oxide terminated surface of the aluminum, gallium, andnitrogen containing material may be treated chemically to encourage theformation of dangling hydroxyl groups (among other chemical species)that will form temporary or weak chemical or van der Waals bonds whenthe surfaces are brought into contact, which are subsequently madepermanent when treated at elevated temperatures and elevated pressures.

In an example, the method includes forming an n-type contact regionoverlying an exposed portion of the n-type aluminum, gallium, andnitrogen containing material or overlying an exposed portion of a n-typegallium and nitrogen containing material overlying the n-type aluminum,gallium, and nitrogen containing material; forming a patterneddielectric region overlying a portion of the n-type contact region; andforming a thickness of conformal metal material overlying the patterneddielectric region; wherein the p-type aluminum, gallium, and nitrogencontaining material is configured as a ridge waveguide structure to forma p-type ridge structure. In an example, the dielectric region iscomprised of silicon oxide or silicon nitride. In an example, the methodincludes forming a ridge waveguide region in or overlying the n-typealuminum, gallium, and nitrogen containing material to form an n-typeridge structure; forming a second conductive oxide region overlying then-type aluminum, gallium, and nitrogen containing material or an exposedportion of an n-type gallium and nitrogen containing material overlyingthe n-type aluminum, gallium, and nitrogen containing material; andforming a metal material overlying the transparent oxide region.

In an example, the handle substrate is selected from a semiconductor, ametal, or a dielectric or combinations thereof. In an example, thehandle substrate is selected from sapphire, silicon carbide, aluminumnitride, aluminum oxy-nitride, copper, aluminum, silicon containingmetal filled vias, or others. In an example, the bonding comprisingthermal bonding, plasma activated bonding, anodic bonding, chemicalbonding, or combinations thereof. In an example, the surface region ofthe gallium and nitrogen containing substrate is configured in a polar,semipolar, or non-polar orientation.

In an example, the method further comprising forming a laser cavity isoriented in a c-direction, a projection of a c-direction, anm-direction, or an a-direction and forming a pair of cleaved facetsusing a cleave propagated through both the handle substrate material andthe gallium and nitrogen containing material. The method also furthercomprising forming a laser cavity is oriented in a c-direction or aprojection of a c-direction and forming a pair of etched facets.

In an example, the handle substrate is a silicon carbide; and furthercomprising separating a plurality of laser dice by initiating a cleavingprocess on the silicon carbide substrate material. In an example, thehandle substrate is a sapphire substrate material; and furthercomprising separating a plurality of laser dice by initiating a cleavingprocess on the sapphire substrate material. In an example, the methodfurther comprises separating a plurality of laser dice by initiating acleaving process on the handle substrate.

In an example, the present invention provides a method for fabricating alaser diode device. The method includes providing a gallium and nitrogencontaining substrate member comprising a surface region, a releasematerial overlying the surface region, an n-type aluminum, gallium, andnitrogen containing material; an active region overlying the n-typealuminum, gallium, and nitrogen containing material, a p-type aluminum,gallium, and nitrogen containing material; and a first transparentconductive oxide region overlying the p-type aluminum, gallium, andnitrogen containing material, and an interface region overlying theconductive oxide material. The method includes bonding the interfaceregion to a handle substrate; and subjecting the release material to anenergy source to initiate release of the gallium and nitrogen containingsubstrate member. In an example, the method includes forming a ridgestructure configured with the n-type aluminum, gallium, and nitrogencontaining material, and forming a dielectric material overlying then-type gallium and nitrogen containing material, and forming a secondtransparent conductive oxide material overlying an exposed portion ofthe n-type aluminum, gallium, and nitrogen containing material or anexposed portion of an n-type gallium and nitrogen containing materialoverlying the n-type aluminum, gallium, and nitrogen containing materialsuch that active region is configured between the first transparentconductive oxide material and the second conductive oxide material tocause an optical guiding effect within the active region.

In an alternative example, the present invention provides a method forfabricating a laser diode device. The method includes providing agallium and nitrogen containing substrate member comprising a surfaceregion, a release material overlying the surface region, an n-typealuminum, gallium, and nitrogen containing material; an active regionoverlying the n-type aluminum, gallium, and nitrogen containingmaterial, a p-type aluminum, gallium, and nitrogen containing material;and a first transparent conductive oxide region overlying the p-typealuminum, gallium, and nitrogen containing material or over a p-typegallium and nitrogen containing material, and an interface regionoverlying the conductive oxide material. The method includes bonding theinterface region to a handle substrate and subjecting the releasematerial to an energy source to initiate release of the gallium andnitrogen containing substrate member in no specific order. In anexample, a second transparent conductive oxide material is disposedoverlying an exposed portion of the n-type aluminum, gallium, andnitrogen containing material or over an exposed portion of the n-typegallium, and nitrogen containing material such that active region isconfigured between the first transparent conductive oxide material andthe second conductive oxide material. The method includes forming aridge structure in the second conductive oxide layer to form to cause alateral optical guiding effect within the active region. Forming adielectric material overlying the second conductive oxide layer,exposing a portion of the second conductive oxide layer on the top ofthe ridge, and forming a metal contact layer to the exposed portion ofthe second conductive oxide.

In an alternative example, the present invention provides a method forfabricating a laser diode device. The method includes providing agallium and nitrogen containing substrate member comprising a surfaceregion, a release material overlying the surface region, an n-typealuminum, gallium, and nitrogen containing material; an active regionoverlying the n-type aluminum, gallium, and nitrogen containingmaterial, a p-type aluminum, gallium, and nitrogen containing material;and a first transparent conductive oxide region overlying the p-typegallium and nitrogen containing material, and an interface regionoverlying the conductive oxide material. The method includes bonding theinterface region to a handle substrate and subjecting the releasematerial to an energy source to initiate release of the gallium andnitrogen containing substrate member in no particular order. The methodincludes forming an n-type contact region overlying an exposed portionof the n-type aluminum, gallium, and nitrogen containing material or anexposed portion of an n-type gallium and nitrogen containing materialoverlying the n-type aluminum, gallium, and nitrogen containingmaterial; forming a patterned second transparent oxide region overlyinga portion of the n-type contact region; and forming a thickness of metalmaterial overlying the patterned transparent oxide region; wherein thep-type aluminum, gallium, and nitrogen containing material is configuredas a ridge waveguide structure to form a p-type ridge structure.

In an example, the present invention provides a method for fabricating alaser diode device. The method includes providing a gallium and nitrogencontaining substrate member comprising a surface region, a releasematerial overlying the surface region, an n-type aluminum, gallium, andnitrogen containing material; an active region overlying the n-typealuminum, gallium, and nitrogen containing material, a p-type aluminum,gallium, and nitrogen containing material; and a first transparentconductive oxide material overlying the p-type aluminum, gallium, andnitrogen containing material, and an interface region overlying theconductive oxide material. The method includes bonding the interfaceregion to a handle substrate and subjecting the release material to anenergy source to initiate release of the gallium and nitrogen containingsubstrate member in no particular order. The method includes forming acavity member comprising a waveguide structure, a first end, and asecond end and forming the first end and second end by initiating acleaving process in the handle substrate material. In an example, alength of the cavity member is defined by the first cleaved end and thesecond cleaved end. The length of the cavity member is less than about1500 um, less than about 1000 um, less than about 600 um, less thanabout 400 um, or less than about 200 um.

In an example, the present invention provides a method for fabricating alaser diode device. The method includes providing a gallium and nitrogencontaining substrate member comprising a surface region, the surfaceregion characterized by a nonpolar or semipolar orientation; a releasematerial overlying the surface region, an n-type aluminum, gallium, andnitrogen containing material; an active region overlying the n-typealuminum, gallium, and nitrogen containing material, a p-type aluminum,gallium, and nitrogen containing material; and an interface regionoverlying the p-type aluminum, gallium, and nitrogen containingmaterial. The method includes bonding the interface region to a handlesubstrate; subjecting the release material to an energy source toinitiate release of the gallium and nitrogen containing substrate memberand forming a cavity member comprising a waveguide structure, a firstend, and a second end. The method includes forming the first end andsecond end by initiating a cleaving process in the handle substratematerial.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1a illustrates an epitaxial structure including sacrificial releaselayer, n-type aluminum, gallium, and nitrogen containing material, andactive region and p-type aluminum, gallium, and nitrogen containingmaterial is grown on bulk gallium and nitrogen containing substrate inan example.

FIG. 1b illustrates a transparent conductive oxide such as GA2O3 isdeposited on the p-side (epi-surface) of the wafer in an example.Optionally, a metal contact layer could be deposited on the GA2O3.

FIG. 1c illustrates a GA2O3+epi-structure+GaN substrate bonded to ahandle (carrier wafer) which could be a number of different materialsincluding aluminum nitride, silicon carbide, sapphire, or other.Indirect bonding or direct bonding could be used for this step in anexample.

FIG. 1d illustrates a GaN substrate is removed via one of severalpossible processes including PEC etching, laser ablation, CMP, etc. Forsome of these processes, a sacrificial layer may be necessary in anexample. After substrate removal, a thin gallium and nitrogen containingepi-membrane will be left on top of the Ga2O3 and carrier wafer. Somep-side processing prior to bonding may be necessary depending on thefinal desired LD structure. The bonded epitaxially grown material willbe thin <5 um. The laser structure itself will be <1.5 um of that.

FIG. 2a is a simplified schematic of epi-structure grown on GaNsubstrate including a sacrificial layer in an example.

FIG. 2b is a simplified schematic of epi-structure grown on GaNsubstrate with a transparent conductive oxide such as Ga2O3 deposited ontop of the p-type aluminum, gallium, and nitrogen containing materialand a carrier wafer bonded to the top of the stack in an example.

FIG. 2c is a simplified schematic of epi-structure with conductive oxideand carrier wafer after the gallium and nitrogen containing substratehas been removed in an example.

FIG. 2d is a simplified schematic of epi-structure with conductive oxideand carrier wafer after the gallium and nitrogen containing substratehas been removed in an example. The structure has been flipped over suchthat the carrier wafer is now the bottom of the stack.

FIG. 3a is an example schematic cross section of laser waveguide withdouble conductive oxide cladding showing ridge formation in n-typealuminum, gallium, and nitrogen containing material such as AlGaN in anexample.

FIG. 3b is an example schematic cross section of laser waveguide withdouble conductive oxide cladding showing ridge formation in theconductive oxide layer overlying the n-type aluminum, gallium, andnitrogen containing material such as AlGaN in an example.

FIG. 3c is an example schematic cross section of laser waveguide withdouble conductive oxide cladding wherein a gallium oxide carrier waferis used for the p-type TCO cladding. A direct bond is made between thep-type aluminum, gallium, and nitrogen containing material such as AlGaNand a conductive carrier wafer comprised of gallium oxide. The originalsubstrate is then removed and a ridge is formed to provide lateralguiding in the now exposed n-type aluminum, gallium, and nitrogencontaining material. Subsequent TCO layers, passivation layer and metallayers to provide electrical contact are overlaid.

FIG. 3d is an example schematic cross section of laser waveguide withdouble conductive oxide cladding showing ridge formation in p-typealuminum, gallium, and nitrogen containing material such as AlGaN.

FIG. 3e is an example schematic cross section of laser waveguide withdouble conductive oxide cladding showing ridge formation in n-type andin p-type aluminum, gallium, and nitrogen containing material such asAlGaN.

FIG. 3f is an example schematic cross section of laser waveguide withconductive oxide and oxide or dielectric cladding showing ridgeformation in p-type aluminum, gallium, and nitrogen containing materialsuch as AlGaN.

FIG. 4a is an example schematic cross section of an epitaxial structurecontaining AlGaN cladding that could be used for the fabrication of a UVlaser device emitting at approximately 350 nm according to thisinvention.

FIG. 4b is an example schematic cross section of an epitaxial structurecontaining AlInGaN cladding that could be used for the fabrication of aUV laser device emitting at approximately 350 nm according to thisinvention.

FIG. 4c is an example schematic cross section of an epitaxial structurecontaining AlGaN cladding that could be used for the fabrication of a UVlaser device emitting at approximately 300 nm according to thisinvention.

FIG. 4d is an example schematic cross section of an epitaxial structurecontaining AlInGaN cladding that could be used for the fabrication of aUV laser device emitting at approximately 300 nm according to thisinvention.

FIG. 4e is an example schematic cross section of an epitaxial structurecontaining AlGaN cladding that could be used for the fabrication of a UVlaser device emitting at approximately 280 nm according to thisinvention.

FIG. 4f is an example schematic cross section of an epitaxial structurecontaining AlInGaN cladding that could be used for the fabrication of aUV laser device emitting at approximately 280 nm according to thisinvention.

FIG. 5a shows schematic diagrams of direct versus indirect wafer bondingto the handle wafer. In the indirect bonding approach a layer such as ametal is used between the handle wafer and the gallium and nitrogencontaining epitaxial structure.

FIG. 5b is an example illustrating a preferred cleaved facet planealigned to the preferred cleavage plane of the handling wafer, scribingand cleaving the handling wafer will assist the cleaving of the GaNlaser facet. In this example m-plane GaN lasers wafer bonded to InP.Preferred cleaved facet plane must be aligned to the preferred cleavageplane of the handling wafer.

FIG. 6 is an example of a process flow that allows for direct bonding ofgallium and nitrogen containing epi to a carrier wafer and GA2O3.

FIG. 7a is an example of a process that allows for direct/indirectbonding of GaN epi to carrier wafer after the ridge has already beenformed.

FIG. 7b is an example of a process that allows for direct/indirectbonding of gallium and nitrogen containing epi to carrier wafer afterthe ridge has already been formed using adhesion layer.

FIG. 8 is an example illustrating a ridge-less laser structure.

FIG. 9 is an example illustrating die expansion.

FIG. 10 is a top view of a selective area bonding process in an example.

FIG. 11 is a simplified process flow for epitaxial preparation in anexample.

FIG. 12 is a simplified side view illustration of selective area bondingin an example.

FIG. 13 is a simplified process flow of epitaxial preparation withactive region protection in an example.

FIG. 14 is a simplified process flow of epitaxial preparation withactive region protection and with ridge formation before bonding in anexample.

FIG. 15 is a simplified illustration of anchored PEC undercut (top-view)in an example.

FIG. 16 is a simplified illustration of anchored PEC undercut(side-view) in an example.

FIG. 17 is top view of a selective area bonding process with dieexpansion in two dimensions in an example.

DETAILED DESCRIPTION

The present disclosure relates generally to optical techniques. Morespecifically, the present disclosure provides methods and devices usingnonpolar, semi-polar, or polar c-plane oriented gallium and nitrogencontaining substrates for optical applications. In an example, thepresent disclosure describes the fabrication of a high confinementfactor UV laser diode composed of a low index upper and lowertransparent conductive oxide [TCO] cladding layers. In an example, thismethod uses conventional planar growth of a LD epi-structure on either anonpolar, semipolar, or polar c-plane GaN substrates. A transparentconductive oxide (TCO) is then deposited on the free epitaxial surfaceto form a transparent, conductive contact layer with an index ofrefraction lower than GaN or AlGaN films of compositions that can begrown fully strained at the thicknesses needed to provide sufficientconfinement of the optical mode. Examples of TCOs are gallium oxide(Ga2O3) indium tin oxide (ITO) and zinc oxide (ZnO). ITO is thecommercial standard for TCOs, and is used in a variety of fieldsincluding displays and solar cells where a semi-transparent electricalcontact is desired. However, in the UV region ITO will be highlyabsorbing and thus may not be the ideal TCO for UV based laser diodes.ZnO offers the advantage of being a direct gap semiconductor with thesame crystal structure as GaN and can be grown epitaxially on GaN attemperatures relatively low compared to growth temperatures of AlInGaNalloys. The bandgap of ZnO is also sufficiently large and similar to GaN(approx. 3.3 eV) that it will exhibit negligible band-edge absorption ofvisible and near UV wavelengths of light. ZnO can be deposited in avariety of ways such as metal organic chemical vapor deposition, othervapor deposition techniques, and from a solution. In a preferredembodiment, the transparent conductive oxides for UV laser diodecladding is a gallium oxide (for example beta Ga2O3 among otherstoichiometries of gallium oxide). The direct absorption edge of above4.7 eV or <263 nm makes gallium oxide an ideal candidate for UV lasercladding regions. Gallium oxide can be deposited either via sputtering,evaporation, or growth from aqueous solution or via a chemical orphysical vapor deposition. Gallium oxide may be grown epitaxially on theGaN layers via metal organic chemical vapor deposition or molecular beamepitaxy among other growth techniques. Gallium oxide conductivity can becontrolled either by introduction of extrinsic defects such as alloyingwith dopant species such as, but not limited to, nitrogen, zinc andsilicon among others. Conductivity and band-gap can also be controlledby alloying gallium oxide with indium oxide, indium tin oxide alloys,zinc oxide, aluminum oxide and tin oxide among others. In someembodiments the TCO layers may consist of several or more layers ofdifferent composition. For example, a thin (less than 50 nm thick) buthighly conductive gallium oxide contact layer may be used to providegood electrical contact while a thicker (100-200 nm) indium tin oxidelayer is used to provide electrical conductivity and lower loss.

The wafer is then bonded to a handle, with the free-surface of the TCOadjacent to the bonding interface. The bonding can either be direct,i.e. with the TCO in contact with the handle material, or indirect, i.e.with a bonding media disposed between the TCO and the handle material inorder to improve the bonding characteristics. For example, this bondingmedia could be Au—Sn solder, CVD deposited SiO2, a polymer, CVD orchemically deposited polycrystalline semiconductor or metal, etc.Indirect bonding mechanisms may include thermocompression bonding,anodic bonding, glass frit bonding, bonding with an adhesive with thechoice of bonding mechanism dependent on the nature of the bondingmedia.

Thermocompression bonding involves bonding of wafers at elevatedtemperatures and pressures using a bonding media disposed between theTCO and handle wafer. The bonding media may be comprised of a number ofdifferent layers, but typically contain at least one layer (the bondinglayer) that is composed of a relatively ductile material with a highsurface diffusion rate. In many cases this material is either Au, Al, orCu. The bonding stack may also include layers disposed between thebonding layer and the TCO or handle wafer that promote adhesion or actas diffusion barriers should the species in the TCO or handle wafer havea high solubility in the bonding layer material. For example an Aubonding layer on a Si wafer may result in diffusion of Si to the bondinginterface, which would reduce the bonding strength. Inclusion of adiffusion barrier such as silicon oxide or nitride would limit thiseffect. Relatively thin layers of a second material may be applied onthe top surface of the bonding layer in order to promote adhesionbetween the bonding layers disposed on the TCO and handle. Some bondinglayer materials of lower ductility than gold (e.g. Al, Cu etc.) or whichare deposited in a way that results in a rough film (for exampleelectrolytic deposition) may require planarization or reduction inroughness via chemical or mechanical polishing before bonding, andreactive metals may require special cleaning steps to remove oxides ororganic materials that may interfere with bonding.

Metal layer stacks may be spatially non-uniform. For example, theinitial layer of a bonding stack may be varied using lithography toprovide alignment or fiducial marks that are visible from the backsideof the transparent substrate.

Thermocompressive bonding can be achieved at relatively lowtemperatures, typically below 500 degrees Celsius and above 200.Temperatures should be high enough to promote diffusivity between thebonding layers at the bonding interface, but not so high as to promoteunintentional alloying of individual layers in each metal stack.Application of pressure enhances the bond rate, and leads to someelastic and plastic deformation of the metal stacks that brings theminto better and more uniform contact. Optimal bond temperature, time andpressure will depend on the particular bond material, the roughness ofthe surfaces forming the bonding interface and the susceptibility tofracture of the handle wafer or damage to the device layers under load.

The bonding interface need not be composed of the totality of the wafersurface. For example, rather than a blanket deposition of bonding metal,a lithographic process could be used to deposit metal in discontinuousareas separated by regions with no bonding metal. This may beadvantageous in instances where defined regions of weak or no bondingaid later processing steps, or where an air gap is needed. One exampleof this would be in removal of the GaN substrate using wet etching of anepitaxially grown sacrificial layer. To access the sacrificial layer onemust etch vias into either of the two surfaces of the epitaxial wafer,and preserving the wafer for re-use is most easily done if the vias areetched from the bonded side of the wafer. Once bonded, the etched viasresult in channels that can conduct etching solution from the edges tothe center of the bonded wafers, and therefore the areas of thesubstrate comprising the vias are not in intimate contact with thehandle wafer such that a bond would form.

The bonding media can also be an amorphous or glassy material bondedeither in a reflow process or anodically. In anodic bonding the media isa glass with high ion content where mass transport of material isfacilitated by the application of a large electric field. In reflowbonding the glass has a low melting point, and will form contact and agood bond under moderate pressures and temperatures. All glass bonds arerelatively brittle, and require the coefficient of thermal expansion ofthe glass to be sufficiently close to the bonding partner wafers (i.e.the GaN wafer and the handle). Glasses in both cases could be depositedvia vapor deposition or with a process involving spin on glass. In bothcases the bonding areas could be limited in extent and with geometrydefined by lithography or silk-screening process.

Direct bonding between TCO deposited on both the GaN and handle wafers,of the TCO to the handle wafer or between the epitaxial GaN film and TCOdeposited on the handle wafer would also be made at elevatedtemperatures and pressures. Here the bond is made by mass transport ofthe TCO, GaN and/or handle wafer species across the bonding interface.Due to the low ductility of TCOs the bonding surfaces must besignificantly smoother than those needed in thermocompressive bonding ofmetals like gold.

The embodiments of this invention will typically include a ridge of somekind to provide lateral index contrast that can confine the optical modelaterally. One embodiment would have the ridge etched into theepitaxially grown AlGaN cladding layers. In this case, it does notmatter whether the ridge is etched into the p-type AlGaN layer beforeTCO deposition and bonding or into the n-type layer after bonding andremoval of the substrate. In the former case, the TCO would have to beplanarized somehow to provide a surface conducive to bonding unless areflowable or plastically deformable bonding media is used which couldaccommodate large variations in height on the wafer surface. In thelatter case bonding could potentially be done without further modifyingthe TCO layer. Planarization may be required in either case should theTCO deposition technique result in a sufficiently rough TCO layer as tohinder bonding to the handle wafer.

In the case where a ridge is formed either partially or completely withthe TCO, the patterned wafer could be bonded to the handle, leaving airgaps on either side of the ridge, thereby maximizing the index contrastbetween the ridge and surrounding materials.

After p-side ridge processing, TCO is deposited as the p-contact.Following TCO deposition, the wafer is bonded p-side down to a carrierwafer and the bulk of the substrate is removed via laser lift-off orphotochemical etching (PEC). This will require some kind of sacrificiallayer on the n-side of the epi-structure.

Laser ablation is a process where an above-band-gap emitting laser isused to decompose an absorbing sacrificial (Al,In,Ga)N layer by heatingand inducing desorption of nitrogen. The remaining Ga sludge is thenetched away using aqua regia or HCl. This technique can be usedsimilarly to PEC etching in which a sacrificial material between theepitaxial device and the bulk substrate is etched/ablated away resultingin separation of the epitaxial structure and the substrate. Theepitaxial film (already bonded to a handling wafer) can then be lappedand polished to achieve a planar surface.

PEC etching is a photoassisted wet etch technique that can be used toetch GaN and its alloys. The process involves an above-band-gapexcitation source and an electrochemical cell formed by thesemiconductor and the electrolyte solution. In this case, the exposed(Al,In,Ga)N material surface acts as the anode, while a metal paddeposited on the semiconductor acts as the cathode. The above-band-gaplight source generates electron-hole pairs in the semiconductor.Electrons are extracted from the semiconductor via the cathode whileholes diffuse to the surface of material to form an oxide. Since thediffusion of holes to the surface requires the band bending at thesurface to favor a collection of holes, PEC etching typically works onlyfor n-type material although some methods have been developed foretching p-type material. The oxide is then dissolved by the electrolyteresulting in wet etching of the semiconductor. Different types ofelectrolyte including HCl, KOH, and HNO₃ have been shown to be effectivein PEC etching of GaN and its alloys. The etch selectivity and etch ratecan be optimized by selecting a favorable electrolyte. It is alsopossible to generate an external bias between the semiconductor and thecathode to assist with the PEC etching process.

After laser lift-off, TCO is deposited as the n-contact. One version ofthis process flow using laser lift-off is described in FIGS. 4(a) and4(b). Using this method, the substrate can be subsequently polished andreused for epitaxial growth. Sacrificial layers for laser lift-off areones that can be included in the epitaxial structure between the lightemitting layers and the substrate. These layers would have theproperties of not inducing significant amounts of defects in the lightemitting layers while having high optical absorption at the wavelengthsused in the laser lift-off process. Some possible sacrificial layersinclude epitaxially grown layers that are fully strained to thesubstrate which are absorbing either due to bandgap, doping or pointdefectivity due to growth conditions, ion implanted layers where theimplantation depth is well controlled and the implanted species andenergy are tuned to maximize implantation damage at the sacrificiallayer and patterned layers of foreign material which will act as masksfor lateral epitaxial overgrowth.

Sacrificial layers for lift-off of the substrate via photochemicaletching would incorporate at a minimum a low-bandgap or doped layer thatwould absorb the pump light and have enhanced etch rate relative to thesurrounding material. The sacrificial layer can be deposited epitaxiallyand their alloy composition and doping of these can be selected suchthat hole carrier lifetime and diffusion lengths are high. Defects thatreduce hole carrier lifetimes and diffusion length must can be avoidedby growing the sacrificial layers under growth conditions that promotehigh material crystalline quality. An example of a sacrificial layerwould be InGaN layers that absorb at the wavelength of an external lightsource. An etch stop layer designed with very low etch rate to controlthe thickness of the cladding material remaining after substrate removalcan also be incorporated to allow better control of the etch process.The etch properties of the etch stop layer can be controlled solely byor a combination of alloy composition and doping. A potential etch stoplayer would an AlGaN layer with a bandgap higher than the external lightsource. Another potential etch stop layer is a highly doped n-type AlGaNor GaN layer with reduce minority carrier diffusion lengths and lifetimethereby dramatically reducing the etch rate of the etch stop material.

PEC etching can be done before or after direct/indirect bonding of thefree surface of the TCO to the handle material. In one case, the PECetching is done after bonding of the p-side TCO to the handle materialand the PEC etch releases the III-nitride epitaxial material from thegallium and nitrogen containing substrate. In another case, PEC etchingof the sacrificial layer is done before bonding such that most of thesacrificial layer is removed and the III-nitride epitaxial material isheld mechanically stable on the gallium and nitrogen containingsubstrate via small unetched regions. Such regions can be left unetcheddue to significant decrease in etch rates around dislocations ordefects. TCO is then deposited on the epitaxial material and the TCOfree surface is bonded to a handle wafer that can be composed of variousmaterials. After bonding, mechanical force is applied to the handlewafer and gallium and nitrogen containing substrate to complete therelease of III-nitride epitaxial material from the GaN substrate.

Substrate removal can also be achieved by mechanical lapping andpolishing or chemical-mechanical lapping and polishing, in which casethe substrate cannot be recovered. In cases where the laterallyconfining structure is on the bonded p-side of the wafer the substrateneed only be thinned enough to facilitate good cleaving, in which caselapping and polishing may be an ideal removal technique.

In addition to providing ultra-high confinement active regions, thiswafer bonding technique for the fabrication of Ga-based laser diodes canalso lead to improved cleaved facet quality. Specifically, we describe amethod for fabricating cleaved facets along a vertical plane for NP andSP ridge laser structures grown on bulk gallium and nitrogen containingsubstrates.

Achieving a high quality cleaved facet for NP and SP ridge lasers can beextremely difficult due to the nature of the atomic bonding on thecrystallographic planes that are orthogonal to a laser stripe orientedin the c-direction or the projection of the c-direction. In nonpolarm-plane, the desired ridge orientation is along the c-direction.Therefore, facets must be form on a crystallographic plane orthogonal tothe c-direction (the c-plane). While this can be done in practice, theyield tends to be low and the facet qualities often vary. This is inpart due to the high iconicity and bond strength on the c-plane, whichmake cleaving difficult. In some SP orientations, it is possible toachieve vertical cleavage planes that are orthogonal to the ridgedirection—however, yields also tend to be low. In other SP orientations,vertical cleavage planes orthogonal to the ridge direction simply do notexist. Cleaving in these SP orientations often result in facets that aregrossly angled.

In this wafer bonding process invention the epitaxial laser structuregrown on top of the gallium and nitrogen containing substrate is bondedp-side down on top of a handling wafer. This can be done before/aftertop-side processing depending on the desired resulting LD structure. Thehandling wafer material and crystal orientation is selected to haveeasily achievable vertical cleavage planes (examples of such materialsinclude Si, GaAs, InP, etc.). The LD wafer and the handling wafer can becrystallographically aligned such that the preferable cleavage directionof the handling wafer coincides with the desired cleavage plane of theridge LD structure. The LD wafer and the handling wafer are thendirectly or indirectly bonded together. After bonding, the bulk galliumand nitrogen containing substrate can be removed via PEC etching, laserablation, or CMP.

Since the resulting LD epitaxial film will be thin (<5 um), scribe marksshould be penetrate the epi-film completely and into the bonding wafer.Forcing a clean cleave across the desired crystallographic plane shouldnow be easy since there is limited amount of actual epi-material tobreak. This method may also allow fabrication of cleaved facet LDs oncertain SP orientations that was previously not possible.

The handling wafer can be selected from several possibilities including,but not limited to 6H—SiC, Si, sapphire, MgAl₂O₄ spinel, MgO, ZnO,ScAlMgO₄, GaAsInP, InP, GaAs, TiO₂, Quartz, LiAlO2, AlN.

The above described method can also be extended into the process for dieexpansion. Typical dimensions for laser cavity widths are 1-30 μm, whilewire bonding pads are ˜100 μm wide. This means that if the wire bondingpad width restriction and mechanical handling considerations wereeliminated from the gallium and nitrogen containing chip dimensionbetween >3 and 100 times more laser diode die could be fabricated from asingle epitaxial gallium and nitrogen containing wafer. This translatesto a >3 to 100 times reduction in epitaxy and substrate costs. Incertain device designs, the relatively large bonding pads aremechanically supported by the epitaxy wafer, although they make no useof the material properties of the semiconductor beyond structuralsupport. The current invention allows a method for maximizing the numberof gallium and nitrogen containing laser devices which can be fabricatedfrom a given epitaxial area on a gallium and nitrogen containingsubstrate by spreading out the epitaxial material on a carrier wafersuch that the wire bonding pads or other structural elements aremechanically supported by relatively inexpensive carrier wafer, whilethe light emitting regions remain fabricated from the necessaryepitaxial material.

In an embodiment, mesas of gallium and nitrogen containing laser diodeepitaxy material are fabricated in a dense array on a gallium andnitrogen containing substrate. This pattern pitch will be referred to asthe ‘first pitch’. Each of these mesas is a ‘die’. These die are thentransferred to a carrier wafer at a second pitch where the second pitchis greater than the first pitch. The second die pitch allows for easymechanical handling and room for wire bonding pads positioned in theregions of carrier wafer in-between epitaxy mesas, enabling a greaternumber of laser diodes to be fabricated from a given gallium andnitrogen containing substrate and overlying epitaxy material. This isreferred to as “die expansion,” or other terms consistent with ordinarymeaning for one of ordinary skill in the art.

FIG. 9—Side view illustrations of gallium and nitrogen containingepitaxial wafer 100 before the die expansion process and carrier wafer1206 after the die expansion process. This figure demonstrates a roughlyfive times expansion and thus five times improvement in the number oflaser diodes which can be fabricated from a single gallium and nitrogencontaining substrate and overlying epitaxial material. Typical epitaxialand processing layers are included for example purposes and are n-AlGaNfor n-side waveguide and/or cladding layers 1201, active region 1202,p-AlGaN for p-side waveguide or cladding layers 1203, insulating layers1204, and contact/pad layers 105. Additionally, a sacrificial region1207 and bonding material 1208 are used during the die expansionprocess.

In another embodiment, die expansion can be used to fabricate“ridge-less” lasers in which the epitaxial material of the entire oralmost entire mesa stripe is utilized in the laser. This differs fromthe traditional ridge laser structure where a ridge is etched into theepitaxial material to form an index guided laser. In this embodiment fora ridge-less laser, the entire mesa is used as a gain guided laserstructure. First mesas are etched and transferred onto a carrier wafervia direct/indirect bonding. The gallium and nitrogen containingsubstrate is removed, leaving the etched mesas on the carrier wafer at adie pitch larger than the original die pitch on the gallium and nitrogencontaining carrier wafer. Dielectric material is deposited on thesidewalls of the mesa to insulate the p- and n-contacts. The dielectricmaterial does not cover the entirety of the gallium and nitrogencontaining p-contact surface. Metal or TCO is deposited on the galliumand nitrogen containing p-contact surface to form the p-contacts. Thisis an exemplary process in which a ridge-less LD structure may be formedthrough the invention described in this patent.

FIG. 8 cross-section schematic of a ridge-less laser structurefabricated using the current invention. The epitaxial material 806 istransferred onto a carrier wafer 801 using the techniques discussed inthe current invention. Bonding of the epitaxial material 806 to thecarrier wafer 801 can be done so via indirect metal 802 to metal 802thermo-compressive bonding. The epitaxial material is cladded on the p-and n-side using TCO 804 to provide high modal confinement in the MQWactive region 807. Insulating material 803 is deposited on the sidewallsof the mesa to insulate the p- and n-contacts. Top-side metal padcontact 805 is formed on top of the top side TCO 804.

In an example, the present techniques provide for a method forfabricating a laser diode device. The method includes providing agallium and nitrogen containing substrate member comprising a surfaceregion, a release material overlying the surface region, an n-typegallium and nitrogen containing material such as AlGaN; an active regionoverlying the n-type gallium and nitrogen containing material, anelectron blocking layer overlying the active region, a p-type galliumand nitrogen containing material such as AlGaN; and an interface regionoverlying the p-type gallium and nitrogen containing material. Themethod includes bonding the interface region to a handle substrate; andsubjecting the release material to an energy source, using at least PECetching, to initiate release of the gallium and nitrogen containingsubstrate member, while maintaining attachment of the handle substratevia the interface region. The method also includes forming a contactregion to either or both the n-type gallium and nitrogen containingmaterial or the p-type gallium and nitrogen containing material.

Referring now back to FIG. 6a —The epitaxial LD structure and the GaNsubstrate may be bonded directly or indirectly to a handling wafer.Direct wafer bonding is bonding without the application of intermediatelayers (i.e., GaN directly onto GaAs). Indirect wafer bonding is bondingwith the application of an intermediate adhesion layer. When theadhesion layer material is comprised of a metal alloy, the process isoften referred to as eutectic bonding.

FIG. 6b —For the cleave to translate from the bonding wafer into thethin GaN LD membrane, the two wafers must be crystallographicallyaligned before bonding. Here, the GaN (0001) plane (or the [11-20]direction) for an m-plane LD is aligned with InP (011) plane (or [0-11]direction).

FIG. 7—Wafer bonding is sensitive to surface roughness and topography.Smooth surfaces are typically required for high yield direct waferbonding. Direct wafer bonding of a handling wafer onto the ridge side ofthe LD structure would therefore likely require a pre-etched handlingwafer. The pre-etched handling wafer would allow the wafer bonding tooccur only on the exposed AlGaN ridge and not on the contact pads. Thisis depicted in the cross-sectional schematic in FIG. 3a . The use of apre-etched handling wafer would also be applicable in the case whereindirect bonding is used (FIG. 3b ). Note, this pre-etched handlingwafer is only necessary if there is exists a rough surface topographythat may degrade the wafer bonding yield. A non-etched handling wafermay be used if bonding between two planar wafers is desired.

FIG. 9 is a side view illustration of gallium and nitrogen containingepitaxial wafer 100 before the die expansion process and carrier wafer106 after the die expansion process. This figure demonstrates a roughlyfive times expansion and thus a five times increase in the number oflaser diodes that can be fabricated from a single gallium and nitrogencontaining substrate and overlying epitaxial material. Typical epitaxialand processing layers are included for example purposes and includeAlGaN and/or n-AlGaN for n-side waveguiding and/or cladding layers 101,active region 102, AlGaN and/or p-AlGaN for p-side waveguiding orcladding regions 103, insulating layers 104, and contact/pad layers 105.Additionally, a sacrificial region 107 and bonding material 108 are usedduring the die expansion process.

FIG. 10 is a simplified top view of a selective area bonding process andillustrates a die expansion process via selective area bonding. Theoriginal gallium and nitrogen containing epitaxial wafer 201 has hadindividual die of epitaxial material and release layers defined throughprocessing. Individual epitaxial material die are labeled 202 and arespaced at pitch 1. A round carrier wafer 200 has been prepared withpatterned bonding pads 203. These bonding pads are spaced at pitch 2,which is an even multiple of pitch 1 such that selected sets ofepitaxial die can be bonded in each iteration of the selective areabonding process. The selective area bonding process iterations continueuntil all epitaxial die have been transferred to the carrier wafer 204.The gallium and nitrogen containing epitaxy substrate 201 can nowoptionally be prepared for reuse.

In an example, FIG. 11 is a simplified diagram of process flow forepitaxial preparation including a side view illustration of an exampleepitaxy preparation process flow for the die expansion process. Thegallium and nitrogen containing epitaxy substrate 100 and overlyingepitaxial material are defined into individual die, bonding material 108is deposited, and sacrificial regions 107 are undercut. Typicalepitaxial layers are included for example purposes and are AlGaN and/orn-AlGaN for n-side waveguide or cladding layers 101, active region 102,and AlGaN and/or p-AlGaN for p-side waveguide regions and/or claddingregions 103.

In an example, FIG. 12 is a simplified illustration of a side view of aselective area bonding process in an example. Prepared gallium andnitrogen containing epitaxial wafer 100 and prepared carrier wafer 106are the starting components of this process. The first selective areabonding iteration transfers a fraction of the epitaxial die, withadditional iterations repeated as needed to transfer all epitaxial die.Once the die expansion process is completed, state of the art laserprocessing can continue on the carrier wafer. Typical epitaxial andprocessing layers are included for example purposes and are AlGaN and/orn-AlGaN for n-side waveguide and/or cladding layers 101, active region102, p-AlGaN or AlGaN for p-side waveguide and/or cladding regions 103,insulating layers 104 and contact/pad layers 105. Additionally, asacrificial region 107 and bonding material 108 are used during the dieexpansion process.

In an example, FIG. 13 is a simplified diagram of an epitaxy preparationprocess with active region protection. Shown is a side view illustrationof an alternative epitaxial wafer preparation process flow during whichsidewall passivation is used to protect the active region during any PECundercut etch steps. This process flow allows for a wider selection ofsacrificial region materials and compositions. Typical substrate,epitaxial, and processing layers are included for example purposes andare the gallium and nitrogen containing substrate 100, n-AlGaN and/orAlGaN for n-side cladding and/or waveguiding layers 101, active region102, AlGaN and/or p-AlGaN for p-side waveguiding and/or cladding regions103, insulating layers 104 and contact/pad layers 105. Additionally, asacrificial region 107 and bonding material 108 are used during the dieexpansion process.

In an example, FIG. 14 is a simplified diagram of epitaxy preparationprocess flow with active region protection and ridge formation beforebonding. Shown is a side view illustration of an alternative epitaxialwafer preparation process flow during which sidewall passivation is usedto protect the active region during any PEC undercut etch steps andlaser ridges are defined on the denser epitaxial wafer before transfer.This process flow potentially allows cost saving by performingadditional processing steps on the denser epitaxial wafer. Typicalsubstrate, epitaxial, and processing layers are included for examplepurposes and are the gallium and nitrogen containing substrate 100,AlGaN and/or n-AlGaN for n-side waveguide and/or cladding layers 101,active region 102, AlGaN and/or p-AlGaN for p-side waveguide and/orcladding layers 103, insulating layers 104 and contact/pad layers 105.Additionally, a sacrificial region 107 and bonding material 108 are usedduring the die expansion process.

FIG. 15 is a simplified example of anchored PEC undercut (top-view).Shown is a top view of an alternative release process during theselective area bonding of narrow mesas. In this embodiment a top downetch is used to etch away the area 300, followed by the deposition ofbonding metal 303. A PEC etch is then used to undercut the region 301,which is wider than the lateral etch distance of the sacrificial layer.The sacrificial region 302 remains intact and serves as a mechanicalsupport during the selective area bonding process. Anchors such as thesecan be placed at the ends of narrow mesas as in the “dog-bone” version.Anchors can also be placed at the sides of mesas (see peninsular anchor)such that they are attached to the mesa via a narrow connection 304,which is undercut and will break preferentially during transfer.Geometric features that act as stress concentrators 305 can be added tothe anchors to further restrict where breaking will occur. The bondmedia can also be partially extended onto the anchor to prevent breakagenear the mesa.

FIG. 16 is a simplified view of anchored PEC undercut (side-view) in anexample. Shown is a side view illustration of the anchored PEC undercut.Posts of sacrificial region are included at each end of the epitaxialdie for mechanical support until the bonding process is completed. Afterbonding the epitaxial material will cleave at the unsupported thin filmregion between the bond pads and intact sacrificial regions, enablingthe selective area bonding process. Typical epitaxial and processinglayers are included for example purposes and are AlGaN and/or n-AlGaNfor n-side waveguide and/or cladding layers 101, active region 102,AlGaN and/or p-AlGaN for p-side waveguide and/or cladding layers 103,insulating layers 104 and contact/pad layers 105. Additionally, asacrificial region 107 and bonding material 108 are used during the dieexpansion process. Epitaxial material is transferred from the galliumand nitrogen containing epitaxial wafer 100 to the carrier wafer 106.Further details of the present method and structures can be found moreparticularly below.

FIG. 17 is top view of a selective area bonding process with dieexpansion in two dimensions in an example. The substrate 901 ispatterned with transferrable die 903. The carrier wafer 902 is patternedwith bond pads 904 at both a second and fourth pitch that are largerthan the die pitches on the substrate. After the first bonding, a subsetof the laser die is transferred to the carrier. After the second bondinga complete row of die are transferred.

In an embodiment, a laser diodes emitting in the ultra violet at 350 nmis grown epitaxially on GaN substrates. FIG. 4a shows a schematic crosssection of the structure, which consists of an n-type buffer layer ofGaN overlaying the substrate, a sacrificial region consisting of anIn_(0.1)Ga_(0.9)N/GaN multiquantum well structure, an Al_(0.2)Ga_(0.8)Nn-type cladding overlaying the sacrificial layers, an active regioncomprised of an Al_(0.2)Ga_(0.8)N/GaN multiquantum well structureoverlaid by an Al_(0.3)Ga_(0.8)N electron blocking layer overlaid by anAl_(0.2)Ga_(0.8)N p-type cladding region. The Al_(0.2)Ga_(0.8)N claddingregions can vary in thickness from 50 to 250 nm. The sacrificial regionInGaN wells can vary in number from 1 to 10 with well width varying from1 to 6 nanometers such that the sacrificial layer absorbs light ofwavelength longer than 405 nm. The active region wells are composed ofGaN and the barriers of Al_(0.2)Ga_(0.8)N, which matches the compositionand bandgap of the cladding.

In an embodiment, a laser diodes emitting in the ultra violet at 350 nmis grown epitaxially on GaN substrates using AlInGaN cladding. This hasthe advantage of allowing for the growth of thick cladding layers due tothe closer lattice matching between GaN and various compositions ofAlInGaN. FIG. 4b shows a schematic cross section of the structure, whichconsists of an n-type buffer layer of GaN overlaying the substrate, asacrificial region consisting of an In_(0.1)Ga_(0.9)N/GaN multiquantumwell structure, an (Al_(1-x)In_(x)N)_(y)(GaN)_(1-y) where x=0.17±3 andy=0.3 n-type cladding overlaying the sacrificial layers, an activeregion comprised of an Al_(0.2)Ga_(0.8)N/GaN multiquantum well structureoverlaid by an Al_(0.3)Ga_(0.8)N electron blocking layer overlaid by an(Al_(1-x)In_(x)N)_(y)(GaN)_(1-y) where x=0.17±3 and y=0.3 p-typecladding region. The AlInGaN cladding regions can vary in thickness from50 to 250 nm. The sacrificial region InGaN wells can vary in number from1 to 10 with well width varying from 1 to 6 nanometers such that thesacrificial layer absorbs light of wavelength longer than 405 nm. Theactive region wells are composed of GaN and the barriers ofAl_(0.2)Ga_(0.8)N, which matches the composition and bandgap of thecladding.

In an embodiment, a laser diodes emitting in the ultra violet at 300 nmis grown epitaxially on GaN substrates. FIG. 4c shows a schematic crosssection of the structure, which consists of an n-type buffer layer ofGaN overlaying the substrate, a sacrificial region consisting of anIn_(0.1)Ga_(0.9)N/GaN multiquantum well structure, anAl_(0.45)Ga_(0.55)N n-type cladding overlaying the sacrificial layers,an active region comprised of an Al_(0.35)Ga_(0.65)N/Al_(0.45)Ga_(0.55)Nmultiquantum well structure overlaid by an Al_(0.55)Ga_(0.45)N electronblocking layer overlaid by an Al_(0.45)Ga_(0.55)N p-type claddingregion. The Al_(0.45)Ga_(0.55)N cladding regions can vary in thicknessfrom 50 to 250 nm. The sacrificial region InGaN wells can vary in numberfrom 1 to 10 with well width varying from 1 to 6 nanometers such thatthe sacrificial layer absorbs light of wavelength longer than 405 nm.The active region wells are composed of Al_(0.45)Ga_(0.55)N and thebarriers of Al_(0.35)Ga_(0.65)N, which matches the composition andbandgap of the cladding.

In an embodiment, a laser diodes emitting in the ultra violet at 300 nmis grown epitaxially on GaN substrates using AlInGaN cladding. This hasthe advantage of allowing for the growth of thick cladding layers due tothe closer lattice matching between GaN and various compositions ofAlInGaN. FIG. 4d shows a schematic cross section of the structure, whichconsists of an n-type buffer layer of GaN overlaying the substrate, asacrificial region consisting of an In_(0.1)Ga_(0.9)N/GaN multiquantumwell structure, an (Al_(1-x)In_(x)N)_(y)(GaN)_(1-y) where x=0.17±3 andy=0.78 n-type cladding overlaying the sacrificial layers, an activeregion comprised of an Al_(0.35)Ga_(0.65)N/Al_(0.45)Ga_(0.55)Nmultiquantum well structure overlaid by an Al_(0.55)Ga_(0.45)N electronblocking layer overlaid by an (Al_(1-x)In_(x)N)_(y)(GaN)_(1-y) wherex=0.17±3 and y=0.78 p-type cladding region. The AlInGaN cladding regionscan vary in thickness from 50 to 250 nm. The sacrificial region InGaNwells can vary in number from 1 to 10 with well width varying from 1 to6 nanometers such that the sacrificial layer absorbs light of wavelengthlonger than 405 nm. The active region wells are composed ofAl_(0.35)Ga_(0.65)N and the barriers of Al_(0.45)Ga_(0.55)N, whichmatches the composition and bandgap of the cladding.

In an embodiment, a laser diodes emitting in the ultra violet at 280 nmis grown epitaxially on GaN substrates. FIG. 4e shows a schematic crosssection of the structure, which consists of an n-type buffer layer ofGaN overlaying the substrate, a sacrificial region consisting of anIn_(0.1)Ga_(0.9)N/GaN multiquantum well structure, anAl_(0.55)Ga_(0.35)N n-type cladding overlaying the sacrificial layers,an active region comprised of an Al_(0.45)Ga_(0.55)N/Al_(0.55)Ga_(0.45)Nmultiquantum well structure overlaid by an Al_(0.65)Ga_(0.35)N electronblocking layer overlaid by an Al_(0.55)Ga_(0.35)N p-type claddingregion. The Al_(0.55)Ga_(0.35)N cladding regions can vary in thicknessfrom 50 to 250 nm. The sacrificial region InGaN wells can vary in numberfrom 1 to 10 with well width varying from 1 to 6 nanometers such thatthe sacrificial layer absorbs light of wavelength longer than 405 nm.The active region wells are composed of Al_(0.45)Ga_(0.55)N and thebarriers of Al_(0.55)Ga_(0.45)N, which matches the composition andbandgap of the cladding.

In an embodiment, a laser diodes emitting in the ultra violet at 280 nmis grown epitaxially on GaN substrates using AlInN cladding. This hasthe advantage of allowing for the growth of thick cladding layers due tothe closer lattice matching between GaN and various compositions ofAlInGaN. FIG. 4f shows a schematic cross section of the structure, whichconsists of an n-type buffer layer of GaN overlaying the substrate, asacrificial region consisting of an In_(0.1)Ga_(0.9)N/GaN multiquantumwell structure, an Al_(1-x)In_(x)N where x=0.17±3 n-type claddingoverlaying the sacrificial layers, an active region comprised of anAl_(0.45)Ga_(0.55)N/Al_(0.55)Ga_(0.45)N multiquantum well structureoverlaid by an Al_(0.65)Ga_(0.35)N electron blocking layer overlaid byan Al_(1-x)In_(x)N where x=0.17±3 p-type cladding region. The AlInGaNcladding regions can vary in thickness from 50 to 250 nm. Thesacrificial region InGaN wells can vary in number from 1 to 10 with wellwidth varying from 1 to 6 nanometers such that the sacrificial layerabsorbs light of wavelength longer than 405 nm. The active region wellsare composed of Al_(0.45)Ga_(0.55)N and the barriers ofAl_(0.55)Ga_(0.45)N, which matches the composition and bandgap of thecladding.

In an example, the present invention can be applied to a variety ofapplications, including defense and security, biomedical instrumentationand treatment, germicidal disinfection, water treatment, chemicalcuring, industrial cutting and shaping, industrial metrology, andmaterials processing.

In the field of defense and security, for example, UV lasers are usedfor remote biological and chemical agent detection. In this application,laser based Raman spectroscopy is utilized to measure molecularvibrations to quickly and accurately identify unknown substances. UVlasers have the optimal wavelength for Raman spectroscopy at stand-offdistances, but the current UV-based tactical detection systems are largeand expensive and have limited functionality. In addition to bio-chemagent detection, UV lasers are used for environmental sensing,atmosphere control and monitoring, pollution monitoring, and otherecological monitoring since a myriad of different compounds aredetectable. Other applications within defense and security includeforensics, detection of altered documents, counterfeit currencydetection, and fingerprint detection. In these applications, the deep UVlaser excites fluorescence in the samples, revealing information that isnot detectable with visible illumination.

In biomedicine, UV lasers are used in medical diagnostics applicationsutilizing fluorescence spectroscopy and Raman spectroscopy to detect andcharacterize constituents of particular samples. Examples includeconfocal microscopes, spectrophotometers, flow cytometers, gelelectrophoresis, and DNA analysis equipment. In addition to diagnostics,UV lasers are used in medical therapies and procedures because UV lightis well absorbed by biological matter and organic compounds. Rather thanburning or cutting material, pulsed UV lasers can deposit enough energyto disrupt the molecular bonds of the surface tissue, which effectivelydisintegrates into the air in a tightly controlled manner throughablation rather than burning. Thus UV lasers have the useful propertythat they can remove exceptionally fine layers of surface material withalmost no heating or change to the remainder of the material, which isleft intact. These properties make UV lasers well suited to precisionmicromachining organic material (including certain polymers andplastics), or delicate surgeries such as eye surgery LASIK. UV lasersalso have applications in treating a variety of dermatologicalconditions including psoriasis, vitiligo, atopic dermatitis, alopeciaareata and leukoderma, all of which have particular absorptions in theUV range.

Additionally, UV lasers can be used for germicidal disinfectionapplications deep UV light at particular wavelengths kill microorganismsin food, air, and water (purification). The UV laser light is effectivein destroying the nucleic acids in these organisms so that their DNA isdisrupted by the UV radiation, leaving them unable to perform vitalcellular functions. The wavelength of UV that causes this effect is rareon Earth as the atmosphere blocks it. As a result, using UV laserdevices in certain environments like circulating air or water systemscreates a deadly effect on micro-organisms such as pathogens, virusesand molds that are in these environments. Coupled with a filtrationsystem, UV lasers can remove harmful micro-organisms from theseenvironments. The application of UV light to disinfection has been anaccepted practice since the mid-20th century. It has been used primarilyin medical sanitation and sterile work facilities. Increasingly it wasemployed to sterilize drinking and wastewater, as the holding facilitieswere enclosed and could be circulated to ensure a higher exposure to theUV. In recent years UV sterilization has found renewed application inair sanitation.

In industrial applications, UV lasers are used in inspection andmetrology since the imaging resolution increases with decreasingwavelength of the illumination source. Semiconductor wafer inspectionequipment utilizes UV lasers for basic illumination as well asscattering and elipsometry. Additionally, UV fluorescence is used inindustrial inspection. Lasers in the UV range also permit various typesof non-thermal (“cold”) processing. These processes range from curing ofmaterials such as epoxies, curing of paints and inks in industrialprinting. UV lasers also enable the removal of sub-micrometer-thicklayers of material, marking an object by UV photon induced color changesof the surface, surface processing including annealing, doping andplanarization, Chemical Vapor Deposition (CVD), writing Bragg gratingsinto optical fibers. UV lasers are widely used in high-resolutionphotolithography machines, one of the critical technologies required formicroelectronic chip manufacturing. Current state-of-the-art lithographytools use deep ultraviolet (DUV) light from the KrF and ArF excimerlasers with wavelengths of 248 and 193 nanometers (the dominantlithography technology today is thus also called “excimer laserlithography” which has enabled transistor feature sizes to shrink below45 nanometers. Excimer laser lithography has thus played a critical rolein the continued advance of the so-called Moore's law for the last 20years.

As shown, the present device can be enclosed in a suitable package. Suchpackage can include those such as in TO-38 and TO-56 headers. Othersuitable package designs and methods can also exist, such as TO-9 orflat packs where fiber optic coupling is required and even non-standardpackaging. In a specific embodiment, the present device can beimplemented in a co-packaging configuration such as those described inU.S. Publication No. 2010/0302464, which is incorporated by reference inits entirety.

In other embodiments, the present laser device can be configured in avariety of applications. Such applications include laser displays,metrology, communications, health care and surgery, informationtechnology, and others. As an example, the present laser device can beprovided in a laser display such as those described in U.S. PublicationNo. 2010/0302464, which is incorporated by reference in its entirety.Additionally, the present laser device can also include elements of U.S.Provisional Application No. 61/889,955 filed on Oct. 11, 2013, which isincorporated by reference in its entirety.

While the above is a full description of the specific embodiments,various modifications, alternative constructions and equivalents may beused. As an example, the packaged device can include any combination ofelements described above, as well as outside of the presentspecification. As used herein, the term “substrate” can mean the bulksubstrate or can include overlying growth structures such as a galliumand nitrogen containing epitaxial region, or functional regions such asn-type GaN, combinations, and the like. Additionally, the examplesillustrates two waveguide structures in normal configurations, there canbe variations, e.g., other angles and polarizations. For semi-polar, thepresent method and structure includes a stripe oriented perpendicular tothe c-axis, an in-plane polarized mode is not an Eigen-mode of thewaveguide. The polarization rotates to elliptic (if the crystal angle isnot exactly 45 degrees, in that special case the polarization wouldrotate but be linear, like in a half-wave plate). The polarization willof course not rotate toward the propagation direction, which has nointeraction with the Al band. The length of the a-axis stripe determineswhich polarization comes out at the next mirror. Although theembodiments above have been described in terms of a laser diode, themethods and device structures can also be applied to any light emittingdiode device. Therefore, the above description and illustrations shouldnot be taken as limiting the scope of the present invention, which isdefined by the appended claims.

What is claimed is:
 1. A system comprising: a package; and anultraviolet laser diode device disposed in the package, the deviceoperable at a wavelength of less than 380 nm and greater than 200 nm,the device comprising: a gallium and nitrogen containing substratemember comprising a surface region, a release material overlying thesurface region, an n-type aluminum, gallium, and nitrogen containingmaterial; an active region comprising aluminum, gallium, and nitrogencontaining material overlying the n-type aluminum, gallium, and nitrogencontaining material, a p-type aluminum, gallium, and nitrogen containingmaterial; and a first transparent conductive oxide material with a bandgap energy of greater than 3.2 eV and less than 7.5 eV overlying thep-type aluminum, gallium, and nitrogen containing material, and aninterface region overlying the first transparent conductive oxidematerial, the gallium and nitrogen containing substrate member beingconfigured by subjecting the release material to an energy source toinitiate release of the gallium and nitrogen containing substratemember; and a handle substrate bonded to the interface region.
 2. Thesystem of claim 1, wherein the interface region is comprised of metal, asemiconductor or another transparent conductive oxide; wherein theinterface region comprises a contact material; and wherein the releasematerial is selected from a semiconductor, a metal, or a dielectric. 3.The system of claim 1, wherein the active region comprises a pluralityof quantum well regions; wherein the release material is selected fromGaN, InGaN, AlInGaN, or AlGaN.
 4. The system of claim 1, wherein therelease material is selected from InGaN or AlInGaN.
 5. The system ofclaim 1, further comprising a ridge structure configured with the n-typealuminum, gallium, and nitrogen containing material to form an n-typeridge structure; a dielectric material overlying the n-type aluminum,gallium, and nitrogen containing material; and a second transparentconductive oxide material with a band gap energy of greater than 3.2 eVoverlying an exposed portion of the n-type aluminum, gallium, andnitrogen containing material or overlying an exposed portion of ann-type gallium and nitrogen containing material overlying the n-typealuminum, gallium, and nitrogen containing material such that activeregion is configured between the first transparent conductive oxidematerial and the second transparent conductive oxide material to providean optical guiding effect within the active region, the ridge structureconfigured with at least a pair of side wall regions, and a uppersurface region configured between the pair of side wall regions.
 6. Thesystem of claim 1, further comprising an n-type contact materialoverlying an exposed portion of the n-type aluminum, gallium, andnitrogen containing material or overlying an exposed portion of ann-type gallium and nitrogen containing material overlying the n-typealuminum, gallium, and nitrogen containing material.
 7. The system ofclaim 1, further comprising an n-type contact region overlying anexposed portion of the n-type aluminum, gallium, and nitrogen containingmaterial or overlying an exposed portion of an n-type gallium andnitrogen containing material overlying the n-type aluminum, gallium, andnitrogen containing material; a patterned transparent oxide regionoverlying a portion of the n-type contact region; and a thickness ofmetal material overlying the patterned transparent oxide region; whereinthe p-type aluminum, gallium, and nitrogen containing material isconfigured as a ridge waveguide structure to form a p-type ridgestructure; and wherein the transparent conductive oxide is comprised ofgallium oxide.
 8. The system of claim 1, further comprising: a secondtransparent conductive oxide layer with a band gap energy of greaterthan 3.2 eV overlying the n-type aluminum, gallium, and nitrogencontaining material or overlying an exposed portion of an n-type galliumand nitrogen containing material overlying the n-type aluminum, gallium,and nitrogen containing material such that an active region isconfigured between the first transparent conductive oxide material andthe second transparent conductive oxide layer to provide an opticalguiding influence whereupon the second transparent conductive oxidelayer is configured as a blanket overlying an underlying surface region;a ridge structure configured within at least the second transparentconductive oxide layer to form transparent conductive oxide ridgestructure; an contact region to expose a portion of the secondtransparent oxide layer; and a metal contact material on the exposedportion of the second transparent conductive oxide layer.
 9. The systemof claim 1, wherein the interface region comprises a transparentconductive oxide containing at least one of a gallium, indium or zincmaterial and the handle substrate comprises gallium oxide; and whereinthe handle substrate surface and interface region surface are bondeddirectly.
 10. The system of claim 1, further comprising a ridgewaveguide region in or overlying the n-type aluminum, gallium, andnitrogen containing material; a transparent conductive oxide regionoverlying the n-type aluminum, gallium, and nitrogen containingmaterial; and a metal material overlying the transparent conductiveoxide region; and wherein the transparent conductive oxide region iscomprised of a gallium oxide material; wherein the handle substrate isselected from a semiconductor, a metal, or a dielectric or combinationsthereof.
 11. The system of claim 1, wherein the handle substrate isselected from a sapphire wafer, silicon carbide wafer, aluminum nitridewafer, silicon wafer, gallium arsenide wafer, or an indium phosphidewafer; wherein surface region of the gallium and nitrogen containingsubstrate is configured in a semipolar, polar, or non-polar orientation.12. The system of claim 1, wherein the first transparent conductiveoxide is comprised of a gallium oxide material.
 13. The system of claim1, wherein the handle substrate is a gallium arsenide substrate, indiumphosphide, or silicon carbide material.
 14. A system comprising: apackage; and a laser diode device disposed in the package, the deviceoperable at a wavelength of less than 380 nm and greater than 200 nm,the device comprising: a gallium and nitrogen containing substratemember comprising a surface region, a release material overlying thesurface region, an n-type aluminum, gallium, and nitrogen containingmaterial; an active region overlying the n-type aluminum, gallium, andnitrogen containing material, a p-type aluminum, gallium, and nitrogencontaining material; and a first transparent conductive oxide regionwith an band gap energy of greater than 3.2 eV overlying the p-typealuminum, gallium, and nitrogen containing material, and an interfaceregion overlying the conductive oxide material, the gallium and nitrogencontaining substrate member being configured by subjecting the releasematerial to an energy source to initiate release of the gallium andnitrogen containing substrate member; and a ridge structure, and asecond transparent conductive oxide material with an band gap energy ofgreater than 3.2 eV overlying an exposed portion of the n-type aluminum,gallium, and nitrogen containing material or overlying an exposedportion of a gallium, and nitrogen containing material overlying then-type aluminum, gallium, and nitrogen containing material such thatactive region is configured between the first transparent conductiveoxide material and the second conductive oxide material to provide anoptical guiding effect within the active region.
 15. The system of claim14, wherein the interface region comprises a contact region of metal,semiconductor, or transparent conductive oxide; wherein the releasematerial is a semiconductor, a metal, or a dielectric; wherein theactive region comprises a plurality of quantum well regions; wherein thehandle substrate is a semiconductor, a metal, or a dielectric orcombinations thereof; wherein surface region of the gallium and nitrogencontaining substrate is configured in a semipolar, polar, or non-polarorientation.
 16. The system of claim 14, wherein the first and secondtransparent conductive oxides are comprised of a gallium oxide material.17. A system comprising: a package; and a laser diode device disposed inthe package, the device operable at a wavelength of less than 380 nm andgreater than 200 nm, the device comprising: a gallium and nitrogencontaining substrate member comprising a surface region, a releasematerial overlying the surface region, an n-type aluminum, gallium, andnitrogen containing material; an active region overlying the n-typealuminum, gallium, and nitrogen containing material, a p-type aluminum,gallium, and nitrogen containing material; and a first transparentconductive oxide layer with an band gap energy of greater than 3.2 eVoverlying the p-type gallium and nitrogen containing material, and aninterface region overlying the first transparent conductive oxide layer,the gallium and nitrogen containing substrate member configured bysubjecting the release material to an energy source to initiate releaseof the gallium and nitrogen containing substrate member; a secondtransparent conductive oxide layer with a band gap energy of greaterthan 3.2 eV overlying the n-type aluminum, gallium, and nitrogencontaining material or overlying an exposed portion of an n-type galliumand nitrogen containing material overlying the n-type aluminum, gallium,and nitrogen containing material such that an active region isconfigured between the first transparent conductive oxide layer and thesecond transparent conductive oxide layer to provide an optical guidinginfluence whereupon the second transparent conductive oxide layer isconfigured as a blanket overlying an underlying surface region; a ridgestructure configured within at least the second transparent conductiveoxide layer to provide a transparent conductive oxide ridge structure; acontact region that exposes a portion of the second transparent oxidelayer; and a metal contact material on the exposed portion of the secondtransparent conductive oxide layer.
 18. The system of claim 17, whereinthe interface region comprises a contact region; and further comprisinga ridge waveguide structure; wherein the release material is selectedfrom a semiconductor, a metal, or a dielectric; wherein the activeregion comprises a plurality of quantum well regions; wherein the devicefurther comprises a handle substrate and the handle substrate isselected from a semiconductor, a metal, or a dielectric or combinationsthereof; and wherein at least one of the first transparent conductiveoxide layer or the second transparent conductive oxide layer iscomprised of a gallium oxide material.
 19. The system of claim 17,wherein the first and second transparent conductive oxides are comprisedof a gallium oxide material.